Astyloplatum n. gen.

http://lsid.speciesfile.org/urn:lsid: Orthoptera.speciesfile.org:TaxonName:522679

Type species. Astyloplatum luteolum n. gen. et n. sp., here designated.

Etymology. The name is the combination of the Latinized Greek prefix “a-” (not, against), the word “stylata” (having styles), and the Latin word platum (plate); it is given due to the absence of stylli on the male subgenital plate. The gender of the name is being established as neuter.

Description. Medium size (body length 18–20 mm) and robust (Fig. 1). Coloration. The only known species of yellowish body. Head. Space between antennal sockets 1.5 times wider than the antennal scape (Figs. 2A, B); ocelli rounded, small, and diffuse (Fig.2A); maxillary palps elongated, third and fourth segment similar in size, fifth segment a little longer than the previous ones and slightly dilated at the apex; labial palpi robust, the last segment noticeably dilated and with rounded apex (Fig. 2C). Thorax. Pronotum narrow and smooth, with quadrangular disc and lateral lobes (Fig. 2B); humeral notch not developed; auditory spiracle below the lower margin of the lateral lobe of the pronotum armed with a triangular fold, attached on the mesothorax (Fig. 2C). Sternum lobes are rounded and narrow, without prolongations; mesosternum quadrangular with the anterior margin 1.5 wider than the posterior one; metasternum triangular and narrow. Legs. Fore coxa armed with a spine dorsally. Fore and mid femora unarmed; fore and middle tibiae with four long spines on each ventral margin and one spine on each side of the ventral-apex (Figs. 2D, 4E); hind femur robust, ventrally armed; hind tibia armed with spines dorsally only, apex with three spurs on each side, being the upper and mid one the longer and similar in length (Fig. 2E). Wings. Lanceolate and not exceeding the apex of the abdomen and hind femur, reaching the ninth tergite, MP vein absent; MA vein not forked. (Figs. 1B, 2F). Abdomen. Stridulatory apparatus present on sides of first and second tergites. Ninth tergite unmodified (Fig. 2G); tenth tergite with two plates denticulated on the posterior edge (Fig. 2H), ventrally on the last tergite with two triangular plates denticulated (Fig. 2I). Cerci almost cylindrical, shorth, and without modification (Figs. 2G, H). Paraprocts unmodified. Subgenital plate subtriangular, without stylli but with lateral prolongations and the posterior edge produced between them (Fig. 2J). Phallic complex. Predominantly membranous (Fig. 3), without sclerotized areas, but with microstructures on the dl, as a ti (Fig. 3A); ejv conspicuous and linguiform (Fig. 3B).

Female. Tenth tergite without modification (Figs. 4A). Cerci cylindrical and thin; ovipositor almost as long as the hind femur, slightly curving upward, smooth edges, rounded apex (Figs. 4H); subgenital plate subrectangular without modifications, and with posterior edge rounded (Figs. 4G).

Distribution. The Colombian Andes, on the east Andean slopes between Boyacá and Santander departments.

Comparison. This new genus fits into the characteristics that currently define the tribe Gryllacridini. Astyloplatum n. gen. differs from Camptonotus and Neoeremus in that it has developed wings, reaching near the apex of the abdomen. The other two genera are wingless or with significantly reduced wing vestiges.

Astyloplatum n. gen. differs from Caudafistulus because it has no elongated tubular-shaped subgenital plate. The coloration is ocher for the new genus and not pink as in Caudafistulus rubrinervosus (Serville), which also has a conspicuous central ocellus occupying a large part of the upper region of the rostrum, in contrast to Astyloplatum n. gen., which has reduced and diffused ocelli. The males of Astyloplatum n. gen. do not have articulated stylli, differentiating it from Brachybaenus, and the other three genera previously mentioned in this comparison. This feature may be convergent with Neotropical genera such as Hyperbaenus and Triaenogryllacris Karny.

The subgenital plate of Hyperbaenus is quadrangular and has no conspicuous lateral projections, no denticulated plates on the tenth tergite, and the wings of Hyperbaenus are rectangular in contrast to Astyloplatum n. gen., which are ovoid or cycloid. Triaenogryllacris triaena Karny, 1937 males have the apex of the subgenital plate with three prolongations, but it differs from Astyloplatum luteolum n. gen. et n. sp., because the subgenital plate in the middle of its length is prolonged and thinner towards the apex, in contrast to A. luteolum n. gen. et n. sp., with a subtriangular and not prolonged subgenital plate. Triaenogryllacris species have a completely black or reddish-brown head, with a very conspicuous central ocellus, unlike A. luteolum n. gen. et n. sp., that its head is the same color as the rest of the body and the central ocellus is diffuse.